Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

1. How does CuT prevent conception?

1. Cu ions make uterus unsuitable for implantation.
2. Cu ions make cervix hostile to the sperms.
3. Cu ions suppress sperms motility.
4. Cu ions inhibit ovulation.

2. Which of the following IUDs makes uterus unsuitable for implantation?

1. LNG-20.
2. Multiload 375.
3. Cu7.
4. Lippes loop.

3. Identify the correct statement for IUDs.

1. They slowly release synthetic progesterone in the body.
2. They increase phagocytosis of sperms within the uterus.
3. They block entry of sperms through the cervix.
4. Both (b) and (c).

4. Select the correct matched pair.

1. Hormone releasing IUD - LNG-20.
2. Non-medicated IUD - Progestasert.
3. Copper releasing IUD - Lippes loop.
4. None of these.

5. Assertion: IUDs can cause excess menstrual bleeding and pain.

Reason: IUDs can perforate uterus.

1. Both assertion and reason are true, and reason is the correct explanation of assertion.
2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
3. Assertion is true, but reason is false.
4. Both assertion and reason are false.

1. Mammary glands are modified:

1. Sweat glands.
2. Sebaceous glands.
3. Sudoriferous glands.
4. Lacrimal glands.

2. Identify the incorrectly matched pair.

1. P - Areola.
2. Q - Lactiferous duct.
3. S - Mammary duct.
4. T - Mammary alveoli.

3. Mammary ducts expand to form:

1. Mammary alveoli.
2. Mammary ampullae.
3. Lactiferous ducts.
4. Mammary tubules.

4. What is areola?

1. Grape-like clusters of milk secreting structures.
2. Fatty tissue between the mammary lobes.
3. Circular pigmented area of skin around nipple.
4. Connective tissue that supports the alveoli and ducts.

5. Assertion: The size of breast depends on the amount of adipose tissue.

Reason: The adipose tissue supports the alveoli and the ducts.

1. Both assertion and reason are true, and reason is the correct explanation of assertion.
2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
3. Assertion is true, but reason is false.
4. Both assertion and reason are false.

1. True embryo develops as a result of fusion of:

1. Two polar nuclei of embryo sac.
2. An egg cell and a male gamete.
3. Synergid and male gamete.
4. A male gamete and antipodals.

2. Refer to the given diagram of the embryo of an angiospermous plant with parts labelled P, Q and R. Select the correct statement(s) regarding this.

1. Part 'P' supplies nutrition to the developing embryo.
2. Part 'Q' is the protective sheath of radicle and root cap.
3. Part 'R' is the protective sheath of shoot apex and leaf primordia.
4. The embryo shown in the diagram is present in members of Family Poaceae.

1. (IV) only.
2. (II) and (III) only.
3. (I) and (IV) only.
4. (I), (II), (III) and (IV).

3. Which of the given statements are true?

1. During the development of a dicot embryo, heart-shaped embryo is followed by globular embryo.
2. The part of embryonal axis above the level of cotyledons is epicotyl, while the part below the level of cotyledons is hypocotyl.
3. Monocot seeds possess a single cotyledon, represented by scutellum.

1. (I) and (II).
2. (II) and (III).
3. (I) and (III).
4. (I), (II) and (III).

4. Consider the following parts of an embryonal axis of a dicot seed.

1. Hypocotyl.
2. Epicotyl.
3. Radicle.
4. Plumule.

In which of the following the above parts are correctly arranged from top to base?

1. (III) → (I) → (II) → (IV).
2. (II) → (I) → (III) → (IV).
3. (IV) → (II) → (I) → (III).
4. (III) → (IV) → (II) → (I).

5. In grass family, the cotyledon, is called:

1. Epiblast.
2. Plumule.
3. Scutellum.
4. Perisperm.

1. Which ion is essential for association of both units of ribosome at the time of protein formation?

1. Mg²⁺
2. Mn²⁺
3. CI^-
4. Ca²⁺

2. During translation, how many initiation factors are required in eukaryotes for initiation reactions?

1. 3
2. 6
3. 7
4. 9

3. Which part of mRNA contains untranslated regions (UTR)?

1. 3' end
2. 5' end
3. Either 3' or 5' end
4. Both 5' end and 3' end

4. Name the enzyme that helps in combining amino acid to its particular tRNA?

1. Activating enzyme
2. Amino-acyl tRNA-synthetas
3. PeptidyI transferase
4. Both (a) and (b)

5. From the given list, select the translation machinery.

1. mRNA
2. Ribosomes
3. Amino acids
4. tRNAs
5. Peptidyl transferase
6. Amino acyl tRNA synthetase
7. Pyrophosphatase

1. (1), (2), (3), (4) and (6)
2. (1), (2), (3), (4) and (5)
3. (1), (2), (3), (4), (5) and (6)
4. (1), (2), (3), (4), (5), (6) and (7)

1. Tile rate of alcohol production is measured on the basis of:

1. Amount of sugar present in the medium.
2. Amount of CO₂ produced per unit time.
3. Amount of yeast added in the medium.
4. All of these.

2. A number of chemicals are produced at the time of alcoholic fermentation with the change of nutrient media, pH and aeration. Select such by-product from the following.

1. Phenylethanol.
2. Amyl alcohol.
3. Glycerol.
4. All of these.

3. During alcoholic fermentation of cereals and potato, the crushed food mixed with hot water for obtaining malt is called:

1. Juice.
2. Mash.
3. Wort.
4. None of these.

4. Distilled alcohol with 95% ethanol content is called:

1. Absolute alcohol.
2. Rectified spirit.
3. Gin.
4. Brandy.

5. Assertion: Rhizopus or 1% malt is used in the nutrient medium when it contains complex carbohydrates.

Reason: Yeast does not possess sufficient diastase or amylase. 

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.